2 ROY L. MOODIE 
Fig. 12. Relative size of the brain and spinal cord of a dinosaur. X 1/140. 
The reconstruction is based on outline figures of the body after Matthew and 
is in the main that of Brontosaurus. Osborn’s figures of the vertebrae of Diplo- 
docus, Riggs’ figures of the vertebral columnof Apatosaurus, Marsh’s figures and 
discussion of the brain and sacral casts of Stegosaurus have all been studied in 
making this figure. 
It represents only an approximation to the truth. The heavy line running 
through the body is the brain and spinal cord. It represents the dural cast of the 
vertebral and cephalic spaces and, since we know that in Sphenodon the brain 
occupied only about one-half of the space and that in the lizard (Leche, Der 
Mensch, p. 206) a similar condition obtains, we may assume that the brain and 
spinal cord of the dinosaurs occupied only a fraction of the space. Even allow- 
ing a larger fraction for the head than we do for the lumbar region, the ‘lumbar 
brain’ would be still many times larger than the cephalic brain. 
